The present invention relates to displaying film flexible articles. The invention is particularly applicable to the hanging of x-ray films to the illuminated translucent panel of a light box and will be described with particular reference thereto. It is to be appreciated that the invention will also find application for hanging other sheet material.
In order for doctors to view the images contained on the thin flexible x-ray film, various film illuminators or light boxes have been developed. These film illuminators have a translucent front panel mounted in front of fluorescent or incandescent lamps. Light from the lamp is diffused through the front panel backlighting the x-ray film to facilitate inspection of the x-ray film.
In order to maintain the x-ray film in a fixed position against the illuminated viewing screen, various mounting apparatus's and techniques have been developed. Commonly, a spring clip is mounted at the top of the light box. U.S. Pat. No. 4,698,930 discloses other devices for hanging film that proport to be an improvement over the common spring clip. The first embodiment uses a horizontally recessed groove located on a vertical surface, the bottom of the groove has a ridge extending in an upward fashion. A cover for the groove has a mantle portion the leading edge of which is bent in a downward direction fitting over the top of the ridge and resting on the ridges' backside. The cover is a weighted material which rests on the vertical surface along the bottom edge of the groove. Holding an object in the embodiment, requires urging the cover in an upward fashion and slipping the object between the bottom edge and the vertical surface. Thereafter, the cover is allowed to come back to its resting point pinching the object and holding it fast.
The second embodiment disclosed in U.S. Pat. No. 4,698,930 includes a recessed groove, located within the groove is a horizontally extending pin or pintle which is the mounting means used to effect pivoting of a front cover. In this manner, the cover pivots upon the pin or pintle in the groove creating a space between the bottom edge of the vertical surface. An object is introduced into the space and thereafter the front cover pivots down and holds the object.
Yet a third embodiment, disclosed in U.S. Pat. No. 4,698,930 uses a rounded recessed groove. The inside of the groove is curved in such a manner that a ball placed in the groove rests naturally at a point in the groove between the bottom of the groove and the backside of the front cover. The bottom of the groove slopes downward and forward providing a track for the ball, placing the ball in close proximity to the bottom edge of the front cover. The object held is slipped into the space between the bottom of the front cover and the vertical wall whereupon the ball weighs down the top of the object.
U.S. Pat. No. 4,527,347 shows yet another manner in which gripping of a thin film x-ray is accomplished. A resilient member comprising an anchoring portion, a thinner hinge or pivoting means, and an engaging portion having a pointed portion are used to hold the x-ray film. The engaging portion is supported by a lower horizontal or slightly upwardly sloping part of a profiled frame element. The rear surface of the anchoring portion is fixed to the inner surface of the vertically extending part of the profiled frame element. An inserted x-ray film results in the engaging portion of the resilient member being deflected or bent upwardly, in this manner, the x-ray is held as a result of the pressure exerted when the engaging portion is compressed in its length direction.
A disadvantage with these prior art film hangers is that the film engaging portions require moving parts to hold the x-ray film. This creates the potential for mechanical breakdown of the moving parts, eventually requiring their removal and replacement. Removal of such an integrated piece of the film illuminator is accomplished with great difficulty.
Furthermore, x-ray films are often observed immediately after being processed. The film surface is frequently still damp or soft from the developing chemicals. In using the prior art described, the developing chemicals softened emulsion from the film tend to accumulate within the gripping or fixing sections of these devices. This build-up causes a degradation in the fixing or gripping ability of these devices. Further, the accumulated emulsion tends to stick the gripper to the film impeding release. Therefore, it becomes necessary to either replace or clean the device. This cleaning is difficult due to the inaccessibility of the location needed to be cleaned.
Yet another drawback to the known art is that they do not securely hold sheets of varying thicknesses. Specifically, the prior art apparatae use moving parts, one of such parts being pressed against another part, to secure and hold the sheet. However, when thick and thin sheets are pressed between the same moving parts only the thicker sheet is engaged thereby causing poor, or no holding pressure to the thinner sheet.
The subject invention contemplates a new and improved sheet hanging apparatus that overcomes all of the above referenced problems and others.